1. Technical Field
This disclosure relates to electronic circuits, and more particularly, to efficient detection of input signals.
2. Background
Modern interfaces allow for plug-and-play connection between devices and computing devices. These interfaces allow devices, such as computer peripherals, portable storage devices, and audio/video (A/V) media players, to connect to a host-computing device for relatively easy data transfer. The computing device may be embodied in a traditional personal computer (desktop or notebook), mobile device (tablet, smart phone, e-reader), entertainment device (smart TV), or embedded in a larger system (e.g., a kiosk, vehicle, etc.) The connection and disconnection may occur without rebooting the computing device or turning off the device. Several devices may be simultaneously used without requiring manufacturer-specific device drivers to be installed on the host-computing device.
One example of the above interface is the Universal Serial Bus (USB), which is a standard serial bus interface for connecting devices. The USB Implementers Forum (USB-IF), an industry trade association incorporating companies from the computer and electronics industries, standardizes the design of USB. USB is intended to replace many legacy varieties of serial and parallel ports. Each developed version of the specification increases the data transmission rate and provides downward compatibility to older versions.
A high-speed USB interface utilizes a sideband of communication for managing signal initiation and low power management on the bus on a link between two ports. This sideband is referred to as Low Frequency Periodic Signaling (LFPS). LFPS employs a predetermined frequency range to communicate the initialization and power management information. For example, the third version or generation of the USB interface, the USB 3.0 interface, utilizes LFPS, whereas the previous two versions do not utilize LFPS. To ensure the proper operation of a high-speed interface using the USB 3.0 specification, a receiver must correctly detect high-speed data rates, such as rates of 5-Gigabits-per-second (Gb/s) or 2.5 Gigahertz (GHz). Additionally, to reduce the cost of power management, the receiver may include a LFPS detector for detecting low-speed LFPS signals with a data rate of 10 MHz to 50 MHz in a low-power 3.0 link.
In view of the above, systems and methods for efficient detection of input signals are desired.